Iterative improvement of the best-fit archive spectrum for two example spectra without (left column) and with emission in the line core (right column). Top row: observed spectrum (black line), best-fit archive spectrum (blue), and final best-fit spectrum (red). The black crosses denote the wavelengths and intensities used for the improvement of the fit. 2nd row: temperature stratifications (blue: archive best-fit, red: final best-fit, black: modified HSRA model). The black crosses denote the optical depths corresponding to the wavelengths marked above. The diamond at log τ = 0.2 denotes the 630 nm continuum intensity contribution. Bottom row: stratification of the LOS velocity.